Life sciences p2 feb march 2012 eng version 1

NATIONAL
SENIOR CERTIFICATE
GRADE 12
VERSION 1 (NEW CONTENT) FOR FULL-TIME CANDIDATES
MARKS: 150
TIME: 2½ hours
LIFE SCIENCES P2
FEBRUARY/MARCH 2012
This question paper consists of 16 pages.
Copyright reserved Please turn over

Life Sciences/P2 (Version 1) (Full-time) 2 DBE/Feb.–Mar. 2012
NSC
INSTRUCTIONS AND INFORMATION
Read the following instructions carefully before answering the questions.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Answer ALL the questions.
Write ALL the answers in your ANSWER BOOK.
Start the answers to each question at the top of a NEW page.
Number the answers correctly according to the numbering system used in this
question paper.
Present your answers according to the instructions of each question.
ALL drawings should be done in pencil and labelled in blue or black ink.
Draw diagrams or flow charts only when asked to do so.
The diagrams in this question paper are NOT necessarily drawn to scale.
Do NOT use graph paper.
You may use a non-programmable calculator, protractor and a compass.
Write neatly and legibly.

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SECTION A
QUESTION 1
1.1 Various options are provided as possible answers to the following questions.
Choose the correct answer and write only the letter (A to D) next to the
question number (1.1.1 to 1.1.9) in your ANSWER BOOK, for example
1.1.10 D.
1.1.1 All the organisms in a given area as well as the abiotic factors with
which they interact are best described as a/an …
A
community.
B
ecosystem.
C
habitat.
D
population.
1.1.2 Which of the following is an example of predation?
A
B
C
D
Bees visiting a flower
Ticks on a dog
A lion catching a zebra
A bird's nest in a tree
1.1.3 Which ONE of the following refers to development in some birds
where the eggs hatch outside the body and the young are born
immobile and totally dependent on its parents?
A
Vivipary and precocial development
B
Ovipary and altricial development
C
Vivipary and altricial development
D
Ovipary and precocial development
1.1.4 Which ONE of the following is TRUE about seeds?
A
B
C
D
Protect the gametes
Provide the embryo with food from cotyledons
Develop into a fruit
Develop from an ovary
1.1.5 Which ONE of the following increases the chances of survival of a
species?
A
B
C
D
Living individually
Living in a colony with division of labour
Having random breeding pairs
Hunting for prey with different species

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QUESTIONS 1.1.6 and 1.1.7 are based on the age-gender pyramid
shown below.
Age-gender pyramid of a population (in millions)
Male Female
81–90 years
71–80 years
61–70 years
51–60 years
41–50 years
31–40 years
21–30 years
11–20 years
0–10 years
3 2 1 0 0 1 2 3
1.1.6 The age-gender pyramid shown above is for a developed country
since …
A
B
C
D
the number of newborn are high.
there are more young people than old people.
there are more females than males in each age group.
the life expectancy of the population is high.
1.1.7 Which ONE of the following can be correctly deduced from the age-gender
pyramid shown above?
A
B
C
D
There are less than 2 million people between 0 and 10 years
There are more males than females in the age group
11 to 20 years
The birth and death rates are about the same
There are more females than males who are 50 years and older

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1.1.8 The statements below refer to the action of different contraceptive
methods.
1. Inhibits the secretion of FSH
2. Increases the level of the hormone progesterone
3. Stops the embryo from implanting in the uterus
4. Stops ovulation by inhibiting the development of the follicle
Which combination refers to the action of the oral contraceptive pill
only?
A
1, 2 and 3 only
B
1, 2 and 4 only
C
1, 2, 3 and 4
D
2, 3 and 4 only
1.1.9 The statements below refer to adaptations of flowers for pollination.
1. Male and female flowers are found on different plants
2. Stigma below anthers
3. Male and female gametes mature at the same time
Which combination of adaptations refers to self-pollination?
A
B
C
D
1 and 2 only
1 and 3 only
2 and 3 only
1, 2 and 3 (9 x 2) (18)

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1.2 Give the correct biological term for each of the following descriptions. Write
only the term next to the question number (1.2.1 to 1.2.10) in your ANSWER
BOOK.
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.2.7
1.2.8
1.2.9
1.2.10
A series of changes that take place during the life cycle of an insect
A fluid containing sperm cells
The maximum size of a population that can be supported by a
habitat under the conditions prevailing at any particular time
The relationship between two species in which both benefit from
the association
The use of resources in slightly different ways by different species
in the same habitat, allowing them to co-exist
The variety of species of living organisms that exist on Earth
The elimination of one species by another in a habitat as a result of
dependence on a common resource
The killing of surplus animals by humans to avoid the destruction of
the natural environment
The periodic movement out of and return to a habitat by living
organisms
A group of organisms, sharing similar characteristics, which are
able to interbreed to produce fertile offspring (10)

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1.3 Indicate whether each of the statements in COLUMN I applies to A ONLY,
B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only,
B only, both A and B, or none next to the question number (1.3.1 to 1.3.8) in
the ANSWER BOOK.
COLUMN I COLUMN II
1.3.1 This would have no effect on the
population size
A: Emigration
B: Immigration
1.3.2 A small portion of the population is
counted and then used to work out
the size of the whole population
A: Census
B: Simple sampling
1.3.3 Competition between cows and
goats for grass
A: Inter-specific
B: Intra-specific
1.3.4 A tube that stores sperm cells until
maturation
A: Vas deferens
B: Seminiferous tubules
1.3.5 The cell division that takes place in
the gametophyte generation to form
gametes
A: Meiosis
B: Mitosis
1.3.6 Relationship between two different
species where one species benefits
and the other is harmed
A: Parasitism
B: Commensalism
1.3.7 A change in the composition of
species in a habitat that has never
been inhabited by organisms before
A: Primary succession
B: Secondary succession
1.3.8 The mature community of plants
that remains relatively stable with
few, if any, changes over time
A: Pioneer
B: Climax
(8 x 2) (16)

NSC
1.4 The diagram below represents the events leading to the development of the
foetus in the human uterus.
3
Part of the female reproductive system showing various stages in
the development of a foetus
Identify the following:
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1
4
5
6
Part labelled 1
Cell labelled 2
Cell labelled 3
Structure labelled 4
Part labelled 5
Fluid labelled 6 (6)
TOTAL SECTION A: 50
2

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SECTION B
QUESTION 2
2.1 Study the diagram below showing a longitudinal section through an eye.
A longitudinal section through a human eye
(a)
(b)
(c)
(d)
Long-sightedness
Astigmatism
Cataract
Short-sightedness (4)
(14)
2.1.1
2.1.2
2.1.3
Label parts 2, 3, 4 and 5 respectively.
Name and describe the process that causes part 1 to dilate.
State how the following defects can be treated to improve vision:
(4)
(6)
1
2
3
4
5

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2.2.1
2.2.2
2.2.3
2.2.4
Identify the neuron labelled A.
Name the type of neuron that is connected to structure B.
Explain the effect on the body if the neuron mentioned in
QUESTION 2.2.2, is damaged.
Explain the significance of reflex actions in humans.
(1)
(1)
(3)
(2)
(7)
2.2 Study the diagram below showing a reflex arc.
A
B
Reflex arc

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2.3 Study the graph below showing the hormonal changes during pregnancy.
2.3.1 Identify the following structures:
(a)
(b)
A
B (2)
2.3.2 State the following:
(a)
(b)
Where prolactin is produced
The function of prolactin (2)
2.3.3
2.3.4
2.3.5
Explain the significance of the levels of oestrogen and progesterone
dropping towards the end of pregnancy.
Explain what will happen if structure A breaks down at the end of the
first week of pregnancy.
Suggest the role of oxytocin around week 40 of pregnancy.
(2)
(2)
(1)
(9)
[30]

NSC
QUESTION 3
3.1 The table below shows the changes in population size of a culture of bacteria,
grown in a petri dish in a laboratory at 20 oC.
Time (hours) Number of bacteria
in population
0 10
2 75
4 160
6 280
8 450
10 725
12 900
14 975
16 1 050
18 1 050
3.1.1
3.1.2
Use these results to plot a line graph.
Explain the shape of the graph between:
(9)
(a)
(b)
6–12 hours
16–18 hours
(2)
(2)
3.1.3 Describe how the growth may change if the population of bacteria
is kept at 30 oC instead of 20 oC. (3)
(16)
3.2 A researcher wanted to know how many fish were in a dam. He caught 20 fish
and marked them by clipping out a small section of their tail fins. He then
released them back into the dam. A few days later he caught 25 fish and
found that 8 had been marked.
3.2.1 Estimate the total number of fish in the dam by using the following
formula:
P = F x S
M
P = Estimated total number of fish in the population
F = Number caught and marked in the first catch
S = Number caught in the second catch
M = Number marked in the second catch
Show ALL working. (3)

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3.2.2
3.2.3
Give ONE reason why the method used by the researcher to mark
the fish could have resulted in an inaccurate estimate of the fish
population in the dam.
Explain ONE way in which the researcher could have increased the
reliability of his estimate of the fish population in the dam.
(2)
(2)
(7)
3.3 The birth rate is the number of births per 1 000 people in the population whilst
the death rate is the number of deaths per 1 000 people in the population.
The table below shows the birth and death rates in three countries, A, B and
C, between 1960 and 2000.
Country Year
1960 1988 2000
A Birth rate 15,8 16,2 14,3
Death rate 12,3 11,5 10,9
B Birth rate 34,0 35,4 39,6
Death rate 22,7 21,5 19,4
C Birth rate 32,9 17,5 15,2
Death rate 17,7 7,4 6,6
3.3.1
3.3.2
3.3.3
3.3.4
Which country (A, B or C) had a decreasing birth rate from 1960 to
2000?
Which country (A, B or C) is most likely a developing one?
Give a reason for your answer to QUESTION 3.3.2.
Explain TWO reasons why the death rate in all three countries had
decreased from 1960 to 2000.
(1)
(1)
(1)
(4)
(7)
[30]
TOTAL SECTION B: 60

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SECTION C
QUESTION 4
4.1 A group of Grade 12 learners carried out an investigation to determine the
effect of gibberellin on the germination of seeds.
The following procedure was followed:
• A sample of hazelnut seeds was divided into two groups, A and B.
• A gibberellin solution was added to the seeds in group A.
• Water was added to the seeds in group B.
• Both groups of seeds were allowed to geminate for 16 days.
• The percentage (%) of seeds germinating in the two groups was
recorded.
The results of the investigation are shown in the graph below.
Percentage germination of hazelnut seeds in gibberellin solution and
water over time
100
90
80
70
60
50
40
30
20
10
0
0 4 8 12 16 20
Time (days)
Germination (%)
Gibberellin
Water
4.1.1 Formulate a possible hypothesis for this investigation. (3)

NSC
4.1.4
4.1.5
State TWO ways in which the validity of this investigation could
have been improved.
Give ONE possible reason why seeds of desert plants germinate
only after heavy rains.
(2)
(2)
(10)
4.2 Study the diagram below and answer the questions that follow.
4.2.1
4.2.2
Label the parts numbered 1 and 4.
Write down only the NUMBER of the gland that:
(2)
(a)
(b)
(c )
(d)
Produces the hormone glucagon
Produces a hormone that controls the growth of long bones
Produces an iodine-containing hormone
Produces a hormone that is involved in the re-absorption of
some salts by the kidneys (4)
4.2.3
4.2.4
State TWO similarities between hormones and nerves with regard
to their functions.
State ONE functional difference between hormones and motor
nerves.
(2)
(2)
(10)
4.1.2
4.1.3
Using the information from the graph, determine the percentage
germination of hazelnut seeds on the 10th day with the gibberellin
treatment.
Explain the purpose of group B.
(1)
(2)

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4.3 Describe the role of the hypothalamus and the adrenal glands in bringing
about changes to the blood vessels of the human skin and explain why these
changes take place. Content
Copyright reserved
Synthesis
(17)
(3)
(20)
NOTE: NO marks will be awarded for answers in the form of flow
charts or diagrams.
TOTAL SECTION C:
GRAND TOTAL:
40
150

Life sciences p2 feb march 2012 eng version 1

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